Retrieve Entity Metadata in CRM 2011 using C#

string entityName ="contact";

// Get the metadata for the currently list's entity
// This metadata is used to create a "Property Descriptor Collection"
RetrieveEntityRequest mdRequest = new RetrieveEntityRequest ( )
{ EntityFilters = EntityFilters.All,
LogicalName = entityName,
RetrieveAsIfPublished = false
};

// Execute the request
RetrieveEntityResponse entityResponse = ( RetrieveEntityResponse ) this.ServiceProxy.Execute ( mdRequest );

EntityMetadata entityData = entityResponse.EntityMetadata;



//To Get Option Set Data
var preferdList= ( entityData.Attributes.Where ( p => p.LogicalName == "preferredcontactmethodcode" ) ).ToList ( ).FirstOrDefault ( ); ;

if ( preferdList != null ) {

PicklistAttributeMetadata optionList= preferdList as PicklistAttributeMetadata;
OptionSetMetadata opValues= optionList.OptionSet;
foreach ( var op in opValues.Options ) {

preferedMethod.Add ( new OptionSet { Value = op.Value.Value, Text = op.Label.LocalizedLabels[0].Label.ToString() } );
}

}